1. Field of Invention
The present invention relates to a substrate for an electro-optical device and manufacturing method thereof, an electro-optical device and manufacturing method thereof, and an electronic apparatus. More particularly, the present invention relates to a reflective film structure suitable for a transflective electro-optical device and a method for manufacturing the same.
2. Description of Related Art
A transflective electro-optical device is widely used in portable electronic apparatuses. A transflective liquid crystal display device is currently being used in mobile phones and portable information terminals. Similar to a transmissive liquid crystal display device, the transflective liquid crystal display device can also implement transmissive display by turning on/off a back light. Further, even when the back light is not used, the transflective liquid crystal display device can implement reflective display similarly to a reflective liquid crystal display device by reflecting external light with a reflective film. Thus, the transflective liquid crystal display device has advantages in that it is possible to selectively use the transmissive display or the reflective display and to reduce power consumption by using the reflective display.
Though the transflective liquid crystal display device is constructed to reflect external light with a reflective film and use the reflected light for display, if the reflecting surface of the reflective film is in the state of, for example, a mirror surface, an illusion occurs due to illumination or projection of a background image, such that visibility may be decreased. Therefore, in order to obtain a suitable brightness in the display as well as to prevent illusions due to illumination or projection of the background image, a light scattering reflective surface having a minute unevenness is typically used. A known method involves forming a base layer made of a resin having unevenness on a substrate and forming a reflective film on the base layer, thereby forming the light scattering reflective surface corresponding to the unevenness of the base layer.
In the above transflective liquid crystal display device, as shown in FIGS. 18 and 19, a base opening 112a is provided in each pixel on a base layer 112 having unevenness by coating a photosensitive resin on one of the substrates of a liquid crystal panel, and by performing exposure and developing processes. A reflective film 113 made of a metallic thin film is provided on the base layer 112. A transmissive opening 113a where the reflective film is not formed is provided on a region overlapped with the base opening 112a in plan view. According to this configuration, the light irradiated from a back light (not shown) passing through the transmissive opening 113a and the base opening 112a in each pixel region becomes light for transmissive display. On the other hand, external light incident to the liquid crystal panel and reflected in reflective films 113R, 113G, and 113B in each pixel region becomes light for reflective display.
However, in the conventional transflective liquid crystal display device, there is a problem in that, since the base opening 112a is formed in a window shape with the base layer 112 removed from each pixel region, a bridge shape of a resin portion between adjacent base openings 112a may be delaminated from the substrate when the base layer 112 is developed. Particularly, if the aperture ratio of the transmissive opening 113a increases in each pixel in order to maximize the transmissive display, the width of the bridge part of the resin portion becomes narrower. Therefore, the base layer 112 is easily delaminated. In addition, as shown in FIGS. 18 and 19, when each pixel region has a lengthwise rectangular shape, if the transmissive opening 113a is formed to have a large size, the width of the resin portion between the adjacent base openings 112a arranged in a direction perpendicular to the longitudinal side of the pixel region becomes smaller as shown in the resin portion 113X in FIG. 18. Therefore, the resin portion is more easily delaminated from the substrate.
Once the resin portion is delaminated from the substrate during the process of developing the base layer 112, even if the delaminated resin portion can be re-attached, a defective shape occurs in the base layer 112, such that the shape of the reflective film also causes a defective image. Accordingly, there is a problem in that the product yield is commonly decreased.